scholarly journals High-temperature corrosion behavior of TP91, C22 alloy and C22 based on laser coatings in simulated reducing corrosion environment

Author(s):  
CongCong Liu ◽  
Zongde Liu ◽  
Yuan Gao ◽  
Xinyu Wang ◽  
Chao Zheng

Abstract To explore corrosion characteristics of TP91, C22 alloy and C22 laser coatings in reducing environment caused by low-nitrogen combustion at 500°C-600°C, a synthetic corrosive medium containing 0.2 vol. % H2S-0.1 vol. % O2-N2 were selected. Results showed that the order of corrosion resistance is: C22 laser coatings>C22 alloy>TP91. 550°C was the limit corrosion temperature for C22 alloy and C22 laser coatings. The reason for the strong corrosion resistance of C22 alloy and C22 laser coatings is that a dense layer of Cr-rich corrosion products due to the is produced in the inner layer, thus protecting the matrix from direct corrosion by corrosive gas. Finer grains before corrosion tests and the formation of dense Cr2O3 inner layers in much speedier process were the main reasons for the best corrosion resistance of C22 laser coatings.

2018 ◽  
Vol 775 ◽  
pp. 441-447
Author(s):  
Dong Bok Lee ◽  
Min Jung Kim ◽  
Gyu Chul Cho ◽  
Soon Young Park ◽  
Poonam Yadav

The high-temperature corrosion behavior of Ni3Al+2.9 wt% Cr alloy was studied in SO2-containing environment. Corrosion tests were carried out at 900, 1000, and 1100 °C for 100 h in atmospheric Ar-0.2% SO2 gas. The alloy corroded relatively slowly due mainly to formation of Al2O3 in the scale. Its corrosion kinetics deviated from the parabolic corrosion rate law to a certain extent owing to ensuing scale spallation. This was attributed to (1) stress generated during scaling and the subsequent cooling period, (2) voids that formed due to the Kirkendall effect, and (3) incorporation of sulfur in the scale. The scale that formed after corrosion at 900 °C consisted of the outer NiO scale, middle NiAl2O4 scale, and inner Al2O3 scale. The increased corrosion rate at 1000 and 1100 °C led to formation of the outer NiO scale, and inner Al2O3 scale.


2006 ◽  
Vol 15-17 ◽  
pp. 398-403
Author(s):  
Jee Hoon Choi ◽  
Dong Bok Lee

L12-type Al65.5Ti24.4Cr10.1 alloys were prepared by induction melting followed by thermomechanical treatment. Corrosion tests were performed between 1173 and 1373 K in a flowing Ar-1% SO2 atmosphere for up to 150 hr. The corrosion proceeded mainly via the oxidation reaction. The oxide scale was primarily composed of Al2O3, together with a small amount of TiO2 that appeared mainly in the lower part of the oxide scale during the latter stages of corrosion. The formation of the highly stoichiometric, slowly growing alumina scale on the surface significantly improved the corrosion resistance of the alloys. Neither internal corrosion products nor sulfides were detected.


2013 ◽  
Vol 718-720 ◽  
pp. 52-58
Author(s):  
Sheng Huan Sang ◽  
Yu Feng Duan ◽  
Hui Chao Chen ◽  
Chang Sui Zhao

Corrosion experiments were carried out with metals 20G, 15CrMoG and 12Cr1MoVG under the simulated atmosphere (N2-5%O2-1500μL/L HCl) of superheaters in waste plastic boilers to choose appropriate materials preventing high temperature corrosion. Corrosion dynamic curves were plotted by mass gain per unit area. Metal specimens after corrosion tests were analyzed by SEM-EDS and XRD. The results show that 20G has the poorest anti-corrosion abilities among the three materials; the corrosion process is involved in activation oxidation of chlorine. Addition of Cr in alloys can improve their corrosion resistance in the mixed atmosphere.


2018 ◽  
Vol 36 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Kazuya Kurokawa ◽  
Toto Sudiro ◽  
Tomonori Sano ◽  
Shoji Kyo ◽  
Osamu Ishibashi ◽  
...  

AbstractAn increasing demand for electricity and preserving the environment has become a great driving force for the development of advanced boilers for coal-fired plants to improve their plant efficiency by raising the operating temperature. To achieve this purpose, the development of materials that possess a high mechanical strength and excellent resistance against corrosion at high temperatures is required. Considering such situation, the high-temperature corrosion behavior of SiO2-forming materials such as CrSi2-Ni and CoNiCrAlY-Si alloys in atmospheres containing NaCl and Na2SO4 is introduced. The SiO2 scale plays a significant role in suppressing the inward diffusion of sulfur and chlorine, resulting in the remarkable suppression of the formation of sulfide and chloride at the scale/substrate interface and inside of the substrate. Based on such results, it is emphasized that SiO2-forming materials show outstanding corrosion resistance against atmospheres containing NaCl and Na2SO4.


Alloy Digest ◽  
1972 ◽  
Vol 21 (10) ◽  

Abstract INCONEL ALLOY 671 is a nickel-chromium alloy having excellent resistance to high-temperature corrosion. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-180. Producer or source: Huntington Alloy Products Division, An INCO Company.


Alloy Digest ◽  
2013 ◽  
Vol 62 (7) ◽  

Abstract ATI 441 is a low-carbon and low-nitrogen ferritic stainless steel with 18 Cr and columbium. The alloy is typically used for exhaust system components. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming. Filing Code: SS-1150. Producer or source: Allegheny Technologies Inc..


Alloy Digest ◽  
1982 ◽  
Vol 31 (6) ◽  

Abstract Type HN is an iron-chromium-nickel alloy containing sufficient chromium for good high-temperature corrosion resistance and with nickel content in excess of the chromium. This alloy has properties somewhat similar to the more widely used ACI Type HT alloy but with better ductility. Type HN is used for highly stressed components in the 1800-2000 F temperature range. It is used in the aircraft, automotive, petroleum, petrochemical and power industries for a wide range of components and parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: SS-410. Producer or source: Various stainless steel casting companies.


Author(s):  
T. Sand ◽  
A. Edgren ◽  
C. Geers ◽  
V. Asokan ◽  
J. Eklund ◽  
...  

AbstractA new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1–2 wt.% silicon. This paper investigates the “silicon effect” on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 °C and 800 °C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 °C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with α- and γ-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl’s by silicon alloying is caused by the appearance of Si-rich phases in the scale.


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